Configuration of an 8-ray 16-wire (a) closely spaced nested wire array. 3-ray 9-wire star arrays with (b) and without (c) precursor.
Ablative forces on the inner wires of 4 and 8-ray closely spaced nested arrays, as a function of inner wire position, with outer diameter of 16 mm (a). Ablative j × B forces on all wires in investigated precursor/nonprecursor star array configuration pairs (b). Non-precursor configurations are those with the “empty” markers. Forces are calculated at I = 0.5 MA, and summed for all wires at a given position/diameter, positive points to the center, negative points outward.
Contour plot of magnetic field (arb. units) around wire pairs in a 16/14 mm 8-wire closely spaced arrays. Array axis is at (0,0). Wire positions denoted by X.
Two-frame shadowgraphy of a 8-wire 16/14 mm load, shot #2396, with no precursor (a), and late plasma on axis (b) 25 ns later, timing (c) and orientation (e). Shadowgram of 8-wire 16/15 mm load, shot #2400 (g), timing (d), and orientation (e). Shadowgram of a 6-wire 16/15 mm load #1344 (h). Original wire positions denoted by yellow lines, array axes by arrows.
Optical streak camera image (a) of a regular cylindrical array, shot #2394 (b). Viewing direction for 8-wire closely spaced loads (c). Streak images of 8-wire 14/16 mm, shot #2395 (d) and 15/16 mm, shot #2400, (e) loads. The precursor plasma in (a) is indicated by arrow.
532 nm shadowgram, probing direction (a) and frame timing (c) for a 16-wire 15.2/16 mm nested array #1068. 532 nm shadowgram (b) and frame timing (d) for a 12-wire 15/16 mm nested array #1352 (d). Gated ICCD image (e) for a 16-wire 15/16 mm nested array #2385. Precursor plasmas on the axes are indicated by arrows.
532 nm shadowgram of early stage ablation in a 16-wire 16/14 mm load, shot #2625 (a). 532 nm (d) and 266 nm (e,f) shadowgrams of a 16-wire 16/14 mm load, shot #2393, (not to scale). Probing directions shown in (c). 532 nm shadowgrams of shot #1170 (g) 16/15.2 mm 16 × 10 μm load of shot #1164 (h) 16/15.2 mm 8 × 15 μm load. The latter two frames were taken at similar time—at 70% of the maximum current.
X-ray yields for cylindrical, nested (ΔR = 4 mm), and CS loads (ΔR = 0.25−1 mm). Error bars display standard deviation within each group. Numbers in parenthesis give the number of shots in each group.
keV x-ray power (PCD with 8 μm Be filter) for 8, 12, and 16-wire closely spaced loads (a). Signals are averages for indicated number of shots. KeV signal for the four 12-wire closely spaced loads (b).
Shadowgrams of 3 × 3 wire load, shot #965, with precursor (a), 3 × 4 wire load, shot #1715 (b), without precursor at the array axis. Array axis denoted by arrow. (c) J × B forces on the wires of star arrays at I = 0.5 MA (by wire position, at diameter).
532 nm shadowgrams of star wire array implosions, with respective probing directions and frame timing. Shot #2629, 18-wire 6-ray star with precursor (a), wires at 16/14/10 mm diameters. Shot #2626, 18-wire 6-ray star, non-precursor (b), 16/12/10 mm dia. Array axes denoted by arrows.
X-ray yields for star arrays in precursor and non-precursor configurations (a). “Total x-ray energy (kJ)” values for shots #2684- #2687 are inferred and not directly comparable with shots #2626- #2636. KeV x-ray signals in GW (b) for nonprecursor (solid) and precursor (dashed) 3-ray stars.
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